The present invention relates to a gas turbine engine, and more particularly to a linkage system which provides a load to each articulating joint to artificially remove internal clearances and reduce vibratory wear when the linkage is in an unloaded condition.
Gas turbine engine exhaust ducts include a liner disposed between the engine exhaust gas path and the engine outer casing or duct. Cooling air is flowed between the cooling liner and duct then discharged over the seals and flaps of the nozzle located at the rear end of the exhaust duct. In order to improve engine operation and performance, exhaust duct cooling air is carefully rationed.
As the engine is subjected to large core pressure gradients at various operating conditions, a rotational flow balance system includes a rotatable control member that is rotated to control the quantity of cooling airflow. Although effective, each rotational flow balance system typically includes a linkage system which may be unloaded during certain operational conditions. While unloaded, the linkage may experience undue wear at connections between the movable components.
Accordingly, it is desirable to provide a linkage system which removes internal clearances and resultant vibratory wear otherwise created by two or more adjacent components vibrating against each other across a clearance without additional component to component wear sites and undesirable modal vibration therefrom.